Acroceridae

Family of flies

Small-headed flies

Temporal range: Late Jurassic–Present

PreꞒ

Pterodontia sp. fly
Scientific classification
Domain:  | Eukaryota
Kingdom:  | Animalia
Phylum:  | Arthropoda
Class:  | Insecta
Superorder:  | Panorpida
Clade:  | Antliophora
Order:  | Diptera
Suborder:  | Brachycera
Superfamily:  | Nemestrinoidea
Family:  | Acroceridae
Leach, 1815
Subfamilies[1]

* Acrocerinae
* †Archocyrtinae
* Cyrtinae
* Ogcodinae
* Panopinae
* Philopotinae

Synonyms

* Cyrtidae
* Ogcodidae
* Oncodidae

The Acroceridae are a small family of odd-looking flies. They have a hump-backed appearance with a strikingly small head, generally with a long proboscis for accessing nectar. They are rare and not widely known. The most frequently applied common names are small-headed flies or hunch-back flies.[2] Many are bee or wasp mimics. Because they are parasitoids of spiders, they also are sometimes known as spider flies.[3]

## Description

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Acroceridae plate from Johann Wilhelm Meigen's Europäischen Zweiflügeligen

The Acroceridae vary in size from small to fairly large, about the size of large bees, with a wingspan over 25 mm in some species. As a rule, both sexes have tiny heads and a characteristic hump-backed appearance because of the large, rounded thorax.

In appearance, they are compact flies without major bristles, but many species have a bee-like hairiness on their bodies, and some are bee or wasp mimics. In most species, the eyes are holoptic in both sexes, the heads seemingly composed mainly of the large faceted eyes. This is in contrast to many insects in which the males have larger (even holoptic) eyes, whereas the females have normal eyes. The squamae are disproportionately large, completely covering the halteres, and the abdomen has an inflated appearance, often practically globular.[4] The tarsi are equipped with large claws with three pulvilli below them.

## Taxonomy

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The Acroceridae are a small family in the Brachycera. They are members of the infraorder Muscomorpha, and DNA studies suggest that they are most closely related to the families Nemestrinidae and Bombyliidae.[5] A 2013 analysis of morphological data suggested the Acroceridae were a sister group to the Asiloidea and Eremoneura.[6]

The roughly 520 species are placed in 50 genera. In 2019, a revised classification of the family based on phylogenetic studies was published, listing five extant subfamilies and one extinct subfamily containing Archocyrtus from the Late Jurassic Karabastau Formation of Kazakhstan.[1]

Obsolete synonyms for Acroceridae include Cyrtidae, Oncodidae, and Ogcodidae.

## Distribution and habitat

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Acroceridae are cosmopolitan in distribution, but nowhere abundant. They appear episodically and in most places are rarely observed; of more than 500 species described, most are known from fewer than 10 specimens. They occur most commonly in semiarid tropical locations.

Eulonchus sapphirinus feeding on Clintonia uniflora

## Behaviour

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As far as is known, all Acroceridae are parasitoids of spiders. They are most commonly collected when a spider from the field is brought into captivity. As in the related families, Bombyliidae and Nemestrinidae, members of the family undergo hypermetamorphosis: the adults do not seek out their hosts; instead, the first-instar larva is a planidium. Females lay large number of eggs, up to 5,000, and after hatching, the planidia seek out spiders. They do not resemble the triungulin of most beetles with a hypermetamorphosis, but do resemble the triungulin of Stylops. The larva can move with a looping movement like a leech or inchworm, and can leap several millimetres into the air. When a spider contacts an acrocerid planidium, the planidium grabs hold, crawls up the spider's legs to its body, and forces its way through the body wall, usually at an articulation membrane. Often, it lodges near a book lung,[4] where it may remain for years before completing its development. Mature larvae pupate outside the host.

Psilodera fasciata, showing the proboscis below the body, holoptic eyes, texture of wings, and bee mimicry

The adults of most species, like various members of the Tabanidae, Nemestrinidae, and Bombyliidae, are nectar feeders with exceptionally long probosces, sometimes longer than the entire body length of the insect. Unlike the other families, however, when not deploying the proboscis for feeding, the Acroceridae carry it lengthwise medially beneath the body, instead of projecting forward. As a result, the proboscis might escape casual notice, though careful inspection may reveal it projecting slightly behind the abdomen.

Flies are usually found in small numbers on plants in July and August in the Palearctic realm.

## References

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1. ^ a b Gillung, Jessica P.; Winterton, Shawn L. (2019). "Evolution of fossil and living spider flies based on morphological and molecular data (Diptera, Acroceridae)". Systematic Entomology. 44 (4): 820–841\. doi:10.1111/syen.12358.
2. ^ Gillung, Jéssica P.; Winterton, Shaun L. (2011). "New genera of philopotine spider flies (Diptera, Acroceridae) with a key to living and fossil genera". ZooKeys (127): 15–27\. doi:10.3897/zookeys.127.1824. PMC 3175128. PMID 21998545.
3. ^ Stubbs, A.; Drake, M. (2014). British Soldierflies and their Allies (2 ed.). Wokingham: British Entomological and Natural History Society. p. 528\. ISBN 9781899935079.
4. ^ a b Richards, O. W.; Davies, R.G. (1977). Imms' General Textbook of Entomology: Volume 1: Structure, Physiology and Development Volume 2: Classification and Biology. Berlin: Springer. ISBN 0-412-61390-5.
5. ^ Wiegmann, Brian M; Yeates, David K; Thorne, Jeffrey L; Kishino, Hirohisa. Time Flies, a New Molecular Time-Scale for Brachyceran Fly Evolution Without a Clock. Syst. Biol. 52(6):745–756, 2003. ISSN 1063-5157 print / ISSN 1076-836X. Online doi:10.1080/10635150390250965
6. ^ Lambkin, Christine L., et al. "The phylogenetic relationships among infraorders and superfamilies of Diptera based on morphological evidence." Systematic Entomology 38.1 (2013): 164-179.

## Further reading

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### Species lists

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* Palaearctic
* Nearctic
* Japan
* Australian and Oceanian
* List of soldierflies and allies of Great Britain

### Identification

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* Sack, P., 1936. Acroceridae. In: Lindner, E. (Ed.). Die Fliegen der Paläarktischen Region 21, pp. 1–36. Keys to Palaearctic species, but in need of revision (in German).
* Narchuk, E.P., 1988. Family Acroceridae. In Bei-Bienko, G. Ya, Keys to the Insects of the European Part of the USSR Volume 5 (Diptera) Part 2, English edition. Keys to Palaearctic species, but in need of revision.
* Przemysław, Trojan, 1962. Acroceridae. In Klucze do oznaczania owadów Polski 28, 23, 1–17. Muchowki = Diptera, 54/58. Warsaw: Państwowe Wydawnictwo Naukowe.

## External links

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Wikimedia Commons has media related to Acroceridae.

* Family description, illustrations
* Images at Diptera.info
* Images and information at BugGuide
* Family Acroceridae at EOL
* Acroceridae in Italian
* Wing venation

* v
* t
* e

Extant Diptera families

* Kingdom: Animalia
* Phylum: Arthropoda
* Class: Insecta
* Subclass: Pterygota
* Infraclass: Neoptera
* Superorder: Holometabola

Suborder Nematocera

| Axymyiomorpha|

* Axymyiidae

|

| Culicomorpha|

| Culicoidea|

* Dixidae (meniscus midges)
* Corethrellidae (frog-biting midges)
* Chaoboridae (phantom midges)
* Culicidae (mosquitoes)

|

Chironomoidea|

* Thaumaleidae (solitary midges)
* Simuliidae (black flies)
* Ceratopogonidae (biting midges)
* Chironomidae (non-biting midges)

| Blephariceromorpha|

* Blephariceridae (net-winged midges)
* Deuterophlebiidae (mountain midges)
* Nymphomyiidae

|

| Bibionomorpha|

| Bibionoidea|

* Bibionidae (march flies, lovebugs)

|

Anisopodoidea|

* Anisopodidae (wood gnats)

Sciaroidea
(fungus gnats)|

* Bolitophilidae
* Cecidomyiidae (gall midges)
* Diadocidiidae
* Ditomyiidae
* Keroplatidae (predatory fungus gnats)
* Lygistorrhinidae (long-beaked fungus gnats)
* Mycetophilidae
* Rangomaramidae (long-winged fungus gnats)
* Sciaridae (dark-winged fungus gnats)

| Perissommatomorpha|

* Perissommatidae

|

| Psychodomorpha|

| Scatopsoidea|

* Canthyloscelidae
* Scatopsidae (minute black scavenger flies, or dung midges)
* Valeseguyidae

|

Psychodoidea|

* Psychodidae (moth flies)

| Ptychopteromorpha|

* Ptychopteridae (phantom crane flies)
* Tanyderidae (primitive crane flies)

|

| Tipulomorpha|

| Trichoceroidea|

* Trichoceridae (winter crane flies)

|

Tipuloidea
(crane flies)|

* Cylindrotomidae (long-bodied crane flies)
* Limoniidae (limoniid crane flies)
* Pediciidae (hairy-eyed craneflies)
* Tipulidae (large crane flies)

Suborder Brachycera

| Asilomorpha|

| Asiloidea|

* Apioceridae (flower-loving flies)
* Apsilocephalidae
* Apystomyiidae
* Asilidae (robber flies)
* Bombyliidae (bee flies)
* Evocoidae
* Hilarimorphidae (hilarimorphid flies)
* Mydidae (mydas flies)
* Mythicomyiidae
* Scenopinidae (window flies)
* Therevidae (stiletto flies)

|

Empidoidea|

* Atelestidae
* Dolichopodidae (long-legged flies)
* Empididae (dagger flies, balloon flies)
* Homalocnemiidae
* Hybotidae (dance flies)
* Oreogetonidae
* Ragadidae

Nemestrinoidea|

* Acroceridae (small-headed flies)
* Nemestrinidae (tangle-veined flies)

Muscomorpha|

| Aschiza|

| Platypezoidea|

* Ironomyiidae (ironic flies)
* Lonchopteridae (spear-winged flies)
* Opetiidae (flat-footed flies)
* Phoridae (scuttle flies, coffin flies, humpbacked flies)
* Platypezidae (flat-footed flies)

|

Syrphoidea|

* Pipunculidae (big-headed flies)
* Syrphidae (hoverflies)

| Schizophora|

| Acalyptratae|

| Conopoidea|

* Conopidae (thick-headed flies)

|

Tephritoidea|

* Pallopteridae (flutter flies)
* Piophilidae (cheese flies)
* Platystomatidae (signal flies)
* Pyrgotidae
* Richardiidae
* Tephritidae (peacock flies)
* Ulidiidae (picture-winged flies)

Nerioidea|

* Cypselosomatidae
* Micropezidae (stilt-legged flies)
* Neriidae (cactus flies, banana stalk flies)

Diopsoidea|

* Diopsidae (stalk-eyed flies)
* Gobryidae
* Megamerinidae
* Nothybidae
* Psilidae (rust flies)
* Somatiidae
* Strongylophthalmyiidae
* Syringogastridae
* Tanypezidae

Sciomyzoidea|

* Coelopidae (kelp flies)
* Dryomyzidae
* Helcomyzidae
* Helosciomyzidae
* Heterocheilidae
* Huttoninidae
* Natalimyzidae
* Phaeomyiidae
* Ropalomeridae
* Sciomyzidae (marsh flies)
* Sepsidae (black scavenger flies)

Sphaeroceroidea|

* Chyromyidae
* Heleomyzidae
* Nannodastiidae
* Sphaeroceridae (small dung flies)

Lauxanioidea|

* Celyphidae (beetle-backed flies)
* Chamaemyiidae (aphid flies)
* Cremifaniidae
* Lauxaniidae

Opomyzoidea|

* Agromyzidae (leaf miner flies)
* Anthomyzidae
* Asteiidae
* Aulacigastridae (sap flies)
* Clusiidae (lekking, or druid flies)
* Fergusoninidae
* Marginidae
* Neminidae
* Neurochaetidae (upside-down flies)
* Odiniidae
* Opomyzidae
* Periscelididae
* Teratomyzidae
* Xenasteiidae

Ephydroidea|

* Camillidae
* Curtonotidae (quasimodo flies)
* Diastatidae (bog flies)
* Drosophilidae (vinegar and fruit flies)
* Ephydridae (shore flies)
* Mormotomyiidae (frightful hairy fly)

Carnoidea|

* Acartophthalmidae
* Australimyzidae
* Braulidae (bee lice)
* Canacidae (beach flies)
* Carnidae
* Chloropidae (frit flies)
* Inbiomyiidae
* Milichiidae (freeloader flies)

Lonchaeoidea|

* Cryptochetidae
* Lonchaeidae (lance flies)

Calyptratae|

| Muscoidea|

* Anthomyiidae (cabbage flies)
* Fanniidae (little house flies)
* Muscidae (house flies, stable flies)
* Scathophagidae (dung flies)

|

Oestroidea|

* Calliphoridae (blow-flies: bluebottles, greenbottles)
* Mesembrinellidae
* Mystacinobiidae (New Zealand batfly)
* Oestridae (botflies)
* Rhiniidae
* Rhinophoridae
* Sarcophagidae (flesh flies)
* Tachinidae (tachina flies)
* Ulurumyiidae

Hippoboscoidea|

* Glossinidae (tsetse flies)
* Hippoboscidae (louse flies)
* Nycteribiidae (bat flies)
* Streblidae (bat flies)

| Stratiomyomorpha|

| Stratiomyoidea|

* Pantophthalmidae (timber flies)
* Stratiomyidae (soldier flies)
* Xylomyidae (wood soldier flies)

|

Tabanomorpha|

| Rhagionoidea|

* Austroleptidae
* Bolbomyiidae
* Rhagionidae (snipe flies)

|

Tabanoidea|

* Athericidae (water snipe flies)
* Oreoleptidae
* Pelecorhynchidae
* Tabanidae (horse and deer flies)

Vermileonomorpha|

| Vermileonoidea|

* Vermileonidae

|

Xylophagomorpha|

| Xylophagoidea|

* Xylophagidae (awl flies)

|

List of families of Diptera

Taxon identifiers

Acroceridae|

* Wikidata: Q1031499
* Wikispecies: Acroceridae
* ADW: Acroceridae
* AFD: ACROCERIDAE
* BioLib: 17392
* BOLD: 80441
* BugGuide: 7016
* EoL: 517
* EPPO: 1ACROF
* Fauna Europaea: 10880
* Fauna Europaea (new): b00fa1ad-35b8-4cdd-8e27-99fb84c6ff41
* GBIF: 3328
* iNaturalist: 176389
* IRMNG: 101196
* ITIS: 134035
* NBN: NBNSYS0000159303
* NCBI: 92616
* NZOR: b555b2e3-7e29-409d-a955-7ddd6537bb35
* Open Tree of Life: 839765
* Paleobiology Database: 138867

Authority control databases: National |

* Israel

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